Install Samba files
sudo apt-get update && apt-get upgrade
sudo apt-get install samba samba-common-bin
Create a shared directory
sudo mkdir /mnt/samba (for example)
Configure samba
sudo nano /etc/samba/smb.conf
Paste the following
[samba]
Comment = Pi shared folder
Path = /mnt/samba
Browseable = yes
Writeable = Yes
create mask = 0775
directory mask = 0775
Public = yes
valid users = root pi
Can create similar blocks to give direct access to different folders.
Create a Samba user
sudo smbpasswd -a pi
Set the password for pi, as prompted. Then restart samba.
service smbd restart